Apparatus and method for charging control in wireless charging system

ABSTRACT

An apparatus and a method for charge control are provided. The apparatus for charge control may include an integrated direct current-to-direct current (DC/DC) converter configured to step up an output voltage level of a load to be greater than or equal to a supply voltage level set in a power amplifier, and the power amplifier configured to convert a direct current (DC) voltage stepped up by the integrated DC/DC converter into an alternating current (AC) voltage based on a resonant frequency, and to amplify the converted AC voltage. The apparatus for charge control may include a rectification unit configured to convert an AC power received wirelessly into a DC power; and a DC/DC converter configured to step down a voltage level of the DC power to a voltage level required by a load in the receiving mode.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.14/089,112 filed on Nov. 25, 2013, which claims the benefit under 35U.S.C. §119(a) of Korean Patent Application No. 10-2012-0134348 filed onNov. 26, 2012, in the Korean Intellectual Property Office, and under 35USC 119(a) of Korean Patent Application No. 10-2013-0141479, filed onNov. 20, 2013, in the Korean Intellectual Property Office, the entiredisclosures of each of which are hereby incorporated by reference forall purposes.

BACKGROUND 1. Field

The following description relates to a wireless charging system and toan apparatus and a method for charge control.

2. Description of Related Art

An explosive increase in the use of electronic devices has spurredresearch on wireless power transmission technology to alleviate theinconvenience of providing wired power supplies in electronic devicesand the limited capacity of batteries. One wireless power transmissiontechnology uses resonance characteristics of radio frequency (RF)devices in order to transmit power wirelessly. For example, a wirelesspower transmission system using resonance characteristics may include asource configured to supply power, and a target configured to receivesupplied power.

SUMMARY

In one general aspect, there is provided an apparatus for charge controlin a wireless charging system, the apparatus including an alternatingcurrent-to-direct current (AC/DC) converter configured to convert an ACpower received wirelessly through a mutual resonance into a DC power, ina receiving mode, an integrated DC-to-DC (DC/DC) converter configured tostep down a voltage level of the DC power to a voltage level required bya load in the receiving mode, and to step up an output voltage level ofthe load to be greater than or equal to a supply voltage level set in apower amplifier in a transmitting mode, and the power amplifierconfigured to convert the DC voltage stepped up by the integrated DC/DCconverter into an AC voltage based on a resonant frequency, and toamplify the converted AC voltage, in the transmitting mode.

The integrated DC/DC converter may include a first capacitor connectedin parallel to at least one of the AC/DC converter and the poweramplifier, a second capacitor connected in parallel to the load, a firsttransistor of a P-channel metal oxide semiconductor (PMOS) type, thefirst transistor connected in series to the first capacitor, a secondtransistor of an N-channel metal oxide semiconductor (NMOS) type, thesecond transistor connected in parallel to the first transistor, aninductor connected in series to the second transistor, and an outputvoltage determining unit configured to determine a voltage applied tothe second capacitor to be an output voltage of the integrated DC/DCconverter in the receiving mode, and to determine a voltage applied tothe first capacitor to be an output voltage of the integrated DC/DCconverter in the transmitting mode.

The integrated DC/DC converter may further include a driving voltagedetermining unit configured to compare a voltage applied to the secondcapacitor to a voltage applied to the first capacitor and determine ahigher voltage to be a driving voltage of the output voltage determiningunit.

The apparatus may further include a third switch unit configured toconnect the AC/DC converter to the integrated DC/DC converter in thereceiving mode to charge the load with a power, and connect theintegrated DC/DC converter to the power amplifier in the transmittingmode to transmit the power stored in the load.

The apparatus may further include a controller configured to control anoperating time of the first transistor based on a difference between avoltage required by the load and a voltage applied to the secondcapacitor in the receiving mode.

The controller may be configured to control the operating time of thefirst transistor based on a difference between a supply voltage set inthe power amplifier and a voltage applied to the first capacitor.

The load may include a battery charger configured to charge a battery bystoring the DC voltage stepped down by the integrated DC/DC converter,the battery configured to be charged by the battery charger in thereceiving mode, and to transfer a DC voltage to the integrated DC/DCconverter in the transmitting mode, and a first switch unit configuredto connect the battery charger to the battery in the receiving mode, andto break the connection between the battery charger and the battery andconnect the integrated DC/DC converter to the battery in thetransmitting mode.

The apparatus may further include a resonator configured to receive theAC power through a mutual resonance with a wireless power transmitter inthe receiving mode, and to transmit the AC power amplified by the poweramplifier through a mutual resonance with a wireless power receiver inthe transmitting mode.

The apparatus may further include a second switch unit configured toconnect the resonator to the AC/DC converter in the receiving mode, andto break the connection between the resonator and the AC/DC converterand connect the resonator to the power amplifier in the transmittingmode.

In another general aspect, there is provided an apparatus for chargecontrol in a wireless charging system, the apparatus including arectification unit configured to convert an AC power received wirelesslythrough a mutual resonance into a DC power, in a receiving mode, a firstDC/DC converter configured to step down a voltage level of the DC powerto a voltage level required by a load in the receiving mode, a secondDC/DC converter configured to step up an output voltage level of theload to be greater than or equal to a supply voltage level set in apower amplifier in a transmitting mode, and the power amplifierconfigured to convert the DC voltage stepped up by the second DC/DCconverter into an AC voltage based on a resonant frequency, and toamplify the converted AC voltage, in the transmitting mode.

The apparatus may further include a resonator configured to receive theAC power through a mutual resonance with a wireless power transmitter inthe receiving mode, and to transmit the AC power amplified by the poweramplifier through a mutual resonance with a wireless power receiver inthe transmitting mode, a first switch unit configured to connect theresonator to the rectification unit in the receiving mode, and toconnect the resonator to the power amplifier in the transmitting mode, asecond switch unit configured to connect the load to the second DC/DCconverter in the transmitting mode, and a controller configured tocontrol operations of the first switch unit and the second switch unit,based on a user input.

The load may include a battery charger configured to charge a battery bystoring the DC voltage stepped down by the first DC/DC converter, andthe battery configured to be charged by the battery charger in thereceiving mode, and to transfer a DC voltage to the second DC/DCconverter in the transmitting mode.

In still another general aspect, there is provided a method for chargecontrol in a wireless charging system, the method including convertingan AC power received wirelessly through a mutual resonance into a DCpower, in a receiving mode, stepping down a voltage level of the DCpower to a voltage level required by a load, using an integrated DC/DCconverter in the receiving mode, stepping up an output voltage level ofthe load to be greater than or equal to a supply voltage level set in apower amplifier, using the integrated DC/DC converter in a transmittingmode, and converting the stepped up output voltage level into an ACvoltage based on a resonant frequency, and amplifying the converted ACvoltage, in the transmitting mode.

The method may further include determining one of the receiving mode andthe transmitting mode for an apparatus for charge control in a wirelesscharging system, based on a user input.

The stepping down may include determining a voltage applied to the loadto be an output voltage of the integrated DC/DC converter in thereceiving mode.

The stepping up may include determining a voltage applied to the poweramplifier to be an output voltage of the integrated DC/DC converter inthe transmitting mode.

The method may further include receiving the AC power through a mutualresonance between a resonator and a wireless power transmitter in thereceiving mode, and transmitting the AC power amplified by the poweramplifier through a mutual resonance between the resonator and awireless power receiver in the transmitting mode.

In yet another general aspect, there is provided an apparatus for chargecontrol in a wireless charging system, the apparatus including aresonator configured to receive a power through a mutual resonance in areceiving mode, transmit the power through the mutual resonance in atransmitting mode, and transfer an input power to another terminal byreflecting the input power in a relay mode, an integrated DC/DCconverter configured to step down a voltage level of a DC signal outputfrom an AC/DC converter to a voltage level required by a load in thereceiving mode, and to step up a voltage level output from the load tobe greater than or equal to a supply voltage level set in a poweramplifier in the transmitting mode, and a controller configured tocontrol the apparatus for charge control in the wireless charging systemto operate in one of the receiving mode, the transmitting mode, and therelay mode, and increase an input impedance of the resonator to begreater than or equal to a predetermined value.

The controller may be configured to open the resonator by connecting theresonator to the AC/DC converter in the receiving mode, connecting theresonator to the power amplifier in the transmitting mode, andconnecting the resonator to an open port in the relay mode using aswitch.

The controller may be configured to open the resonator by controllingthe integrated DC/DC converter for a supply voltage of “0” volts to besupplied to the power amplifier in the relay mode.

In further another general aspect, there is provided an apparatus forcharge control in a wireless charging system, the apparatus including aresonator configured to receive a power through a mutual resonance in areceiving mode, and reflect an input power in a relay mode, a DC/DCconverter configured to step down a voltage level of a DC signal outputfrom an AC/DC converter to a voltage level required by a load in thereceiving mode, and a controller configured to control the apparatus forcharge control in the wireless charging system to operate in one of thereceiving mode, a transmitting mode, and the relay mode, and increase aninput impedance of the resonator to be greater than or equal to apredetermined value.

The controller may be configured to open the resonator by connecting theresonator to the AC/DC converter in the receiving mode, and connectingthe resonator to an open port in the relay mode using a switch.

The controller may be configured to control the apparatus for chargecontrol in the wireless charging system to operate in the relay modewhen charging of the load is completed.

In still another general aspect, there is provided an apparatus forcharge control in a wireless charging system, the apparatus including aresonator configured to transmit a power through a mutual resonance in atransmitting mode, and reflect an input power in a relay mode, a DC/DCconverter configured to step up a voltage level output from a load to begreater than or equal to a supply voltage level set in a power amplifierin the transmitting mode, and a controller configured to increase aninput impedance of the resonator to be greater than or equal to apredetermined value in the relay mode.

The controller may be configured to open the resonator by connecting theresonator to the power amplifier, and connecting the resonator to anopen port in the relay mode using a switch.

The controller may be configured to open the resonator by controllingthe DC/DC converter for a supply voltage of “0” volts to be supplied tothe power amplifier in the relay mode.

The controller may be configured to control the apparatus for chargecontrol in the wireless charging system to operate in the relay modebased on a user input.

In yet another general aspect, there is provided a method for chargecontrol in a wireless charging system, the method including convertingan AC power received wirelessly into a DC power, stepping down a voltagelevel of the DC power to a voltage level required by a load, using anintegrated DC/DC converter, and transferring the DC power to the load.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless chargingsystem.

FIG. 2 is a diagram illustrating an example of an apparatus for chargecontrol.

FIGS. 3A and 3B are blocks diagram illustrating an example of anapparatus for charge control.

FIG. 4 is a block diagram illustrating another example of an apparatusfor charge control.

FIG. 5 is a block diagram illustrating an example of a wireless chargingsystem.

FIGS. 6 through 8 are diagrams illustrating examples of an integrateddirect current-to-direct current (DC/DC) converter of an apparatus forcharge control.

FIG. 9 is a block diagram illustrating still another example of anapparatus for charge control.

FIG. 10 is a block diagram illustrating yet another example of anapparatus for charge control.

FIG. 11 is a flowchart illustrating an example of a method for chargecontrol.

FIGS. 12A through 14B are diagrams illustrating examples of applicationsfor an apparatus for charge control.

FIGS. 15A through 15B are diagrams illustrating distribution of magneticfield in an example of a feeder and an example of a resonator.

FIGS. 16A and 16B are diagrams illustrating an example of a wirelesspower transmitter.

FIG. 17A is a diagram illustrating distribution of magnetic field withinan example of a resonator based on feeding of a feeding unit.

FIG. 17B is a diagram illustrating examples of equivalent circuits of afeeding unit and a resonator.

FIG. 18 is a diagram illustrating an example of an electric vehiclecharging system.

FIGS. 19A and 19B are block diagrams illustrating other examples ofapparatuses of charge control in a wireless charging system.

FIG. 20 is a diagram illustrating an example of an apparatus for chargecontrol in a wireless charging system in a relay mode.

FIG. 21 is a diagram illustrating another example of an apparatus forcharge control in a wireless charging system.

FIG. 22 is a block diagram illustrating an example of an apparatus forcharge control in a wireless charging system operable in a receivingmode or a relay mode.

FIGS. 23A and 23B are block diagrams illustrating examples ofapparatuses for charge control in a wireless charging system operable ina transmitting mode or a relay mode.

FIG. 24 is a diagram illustrating an example of an apparatus for chargecontrol in a wireless charging system operable in a transmitting mode ora relay mode.

Throughout the drawings and the detailed description, unless otherwisedescribed, the same drawing reference numerals will be understood torefer to the same elements, features, and structures. The drawings maynot be to scale, and the relative size, proportions, and depiction ofelements in the drawings may be exaggerated for clarity, illustration,and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, various changes,modifications, and equivalents of the systems, apparatuses and/ormethods described herein will be apparent to one of ordinary skill inthe art. The progression of processing steps and/or operations describedis an example; however, the sequence of and/or operations is not limitedto that set forth herein and may be changed as is known in the art, withthe exception of steps and/or operations necessarily occurring in acertain order. Also, descriptions of functions and constructions thatare well known to one of ordinary skill in the art may be omitted forincreased clarity and conciseness.

The features described herein may be embodied in different forms, andare not to be construed as being limited to the examples describedherein. Rather, the examples described herein have been provided so thatthis disclosure will be thorough and complete, and will convey the fullscope of the disclosure to one of ordinary skill in the art.

A wireless power transmission system may be implemented by utilizingresonance characteristics of radio frequency (RF) devices. Such awireless power transmission system may include a source that isconfigured to supply power, and a target that is configured to receivethe power supplied by the source.

A scheme of performing a wireless communication between a source and atarget may be an in-band communication scheme, or an out-bandcommunication scheme, or a combination of both. An in-band communicationscheme refers to communication performed between a source and a targetin the same frequency band as that used for power transmission. Anout-band communication scheme refers to communication performed betweena source and a target in a frequency band that is different from afrequency band used for the transmission of power between the source andthe target. FIG. 1 illustrates an example of a wireless charging systemthat includes a source and a target.

Referring to FIG. 1, the wireless power transmission system includes asource 110 and a target 120. The source 110 is a device that isconfigured to supply power wirelessly. The source 110 may be implementedas any electronic device capable of supplying power, such as, forexample, a pad, a terminal, a television (TV), a medical device, and anelectric vehicle. The target 120 is a device that is configured toreceive power wirelessly from the source 110. The target 120 may beimplemented in the form of any electronic devices that requires power,such as, for example, a washing machine, a radio, an electric light, aTV, a pad, a terminal, a tablet personal computer (PC), a medicaldevice, and an electric vehicle.

Referring to FIG. 1, the source 110 includes a variable switching modepower supply (SMPS) 111, a power amplifier (PA) 112, a matching network113, a transmission (TX) controller 114, such as, for example, TXcontrol logic, a communication unit 115, and a power detector 116.

The variable SMPS 111 may generate a direct current (DC) voltage from analternating current (AC) voltage having a frequency of tens of hertz(Hz) output from a power supply. The variable SMPS 111 may output a DCvoltage having a predetermined level, or may output a DC voltage havingan adjustable level under the control of the TX controller 114.

The variable SMPS 111 may control a voltage supplied to the PA 112 basedon a level of power output from the PA 112 so that the PA 112 mayoperate in a saturation region with a high efficiency at all times,thereby enabling a maximum efficiency to be maintained at all levels ofthe output power. In one example, the PA 112 may be a class-E poweramplifier, or may exhibit features of a class-E power amplifier.

In an example in which a fixed SMPS outputting a fixed output voltage isused instead of the variable SMPS 111, a variable DC-to-DC (DC/DC)converter may be used to convert the fixed voltage output from the SMPSto a variable voltage supplied to the PA 112. In this example, thecommon SMPS and the variable DC/DC converter may control a voltagesupplied to the PA 112 based on the level of the power output from thePA 112 so that the PA 112 may operate in the saturation region with highefficiency at all times, thereby maintaining the maximum efficiency atall levels of the output power.

The power detector 116 detects an output current and an output voltageof the variable SMPS 111, and provides the TX controller 114 withinformation regarding the detected current and the detected voltage.Also, the power detector 116 detects an input current and an inputvoltage of the power amplifier 112.

The power amplifier 112 generates power by converting a DC voltagehaving a predetermined level to an AC voltage using a switching pulsesignal in a band in a range of a few kilohertz (kHz) to tens of MHz.Accordingly, the power amplifier 112 converts a DC voltage supplied tothe power amplifier 112 to an AC voltage having a reference resonantfrequency F_(Ref), and generates communication power used forcommunication, or charging power used for charging the target 120, orboth. The communication power and the charging power may be send to andused in a plurality of target devices.

The term “communication power” may be a low power suitable forcommunication purposes, and the communication power may correspond tolow power in a range of 0.1 milliwatt (mW) to 1 mW. The term “chargingpower” may be power suitable for charging a target device, and thecharging power may correspond to high power in a range of 1 mW to 200 Wthat may be consumed by a device load of a target device. In variousexamples described herein, the term “charging” may refer to supplyingpower to a unit or element that is configured to charge a battery orother rechargeable device with power for subsequent consumption. Theterm “charging” may also refer to supplying power to a unit or elementthat is configured to consume power. The units or elements that may becharged include, for example, batteries, displays, sound outputcircuits, main processors, various sensors, and the like.

The term “reference resonant frequency” refers to a resonant frequencythat is nominally used by the source 110. The term “tracking frequency”refers to a resonant frequency that is actually used by the source 110and has been adjusted based on a preset scheme.

The TX controller 114 may be configured to detect a reflected wave ofthe communication power or the charging power, and may be configured todetect a mismatching that occurs between a target resonator 133 and asource resonator 131 based on the detected reflected wave. To detect themismatching between a source resonator 131 and a target resonator 133,the TX controller 114 may, for example, detect an envelope of thereflected wave, a power amount of the reflected wave, or any otherparameter of the reflected wave that is affected by the mismatching.

Under the control of the TX controller 114, the matching network 113compensates for impedance mismatching between the source resonator 131and the target resonator 133 in order to achieve optimal matchingbetween the source resonator 131 and the target resonator 133. Referringto FIG. 1, the matching network 113 may include a plurality of switcheseach connected to a capacitor or an inductor, and the switches may becontrolled by the TX controller 114 to achieve optimal matching.

The TX controller 114 calculates a voltage standing wave ratio (VSWR)based on a voltage level of the reflected wave and a level of an outputvoltage of the source resonator 131 or the power amplifier 112. In theevent that the VSWR is greater than a predetermined value, the TXcontroller 114 may determine that a mismatching has occurred between thesource resonator 131 and the target resonator 133.

In the event that the TX controller 114 detects that the VSWR is greaterthan the predetermined value, the TX controller 114 may compute powertransmission efficiency for each of N tracking frequencies, and maydetermine a tracking frequency F_(Best) providing the best powertransmission efficiency among the N tracking frequencies. Based on theresult, the TX controller 114 may change the reference resonantfrequency F_(Ref) to the tracking frequency F_(Best). In variousexamples, the N tracking frequencies may be set in advance.

The TX controller 114 may adjust a frequency of the switching pulsesignal used by the power amplifier 112. For example, by controlling thefrequency of the switching pulse signal used by the power amplifier 112,the TX controller 114 may generate a modulation signal that may betransmitted to the target 120. For example, the TX controller 114 maytransmit a variety of data (not illustrated in FIG. 1) to the target 120using an in-band communication. The TX controller 114 may also detect areflected wave, and may demodulate a signal received from the target 120based on an envelope of the detected reflected wave.

The TX controller 114 may generate a modulation signal for in-bandcommunication using various techniques. For example, the TX controller114 may generate the modulation signal by turning on or off a switchingpulse signal, by performing delta-sigma modulation or other modulationtechnique. The TX controller 114 may also generate a pulse-widthmodulation (PWM) signal having a predetermined envelope.

The TX controller 114 may determine an initial wireless power that is tobe transmitted to the target 120. The TX controller 114 may determinethe initial wireless power to be transmitted based on: a change in atemperature of the source 110, a battery state of the target 120, achange in an amount of power received by the target 120, and/or a changein a temperature of the target 120.

The source 110 may further include a temperature measurement sensor (notillustrated) that is configured to detect a change in a temperature ofthe source 110. The source 110 may receive, from the target 120,information regarding the battery state of the target 120, the change inthe amount of power received by the target 120, and/or the change in thetemperature of the target 120 by communicating with the target 120.

The TX controller 114 may adjust a voltage supplied to the PA 112 usinga lookup table. The lookup table may be used to store an amount of thevoltage to be adjusted based on the change in the temperature of thesource 110. For example, in response to determining that the temperatureof the source 110 has increased, the TX controller 114 may reduce thevoltage supplied to the PA 112 based on the lookup table.

The communication unit 115 may perform an out-band communication thatemploys a communication channel The communication unit 115 may include acommunication module, such as a ZigBee module, a Bluetooth module, orany other communication module known to one of ordinary skill in theart. The communication unit 115 may transmit data 140 to the target 120through the out-band communication.

The source resonator 131 transfers electromagnetic energy 130 to thetarget resonator 133. For example, the source resonator 131 transfersthe communication power or the charging power to the target 120 viamagnetic coupling with the target resonator 133.

As illustrated in FIG. 1, the target 120 includes a matching network121, a rectification unit 122, a DC/DC converter 123, a communicationunit 124, a reception (RX) controller 125, such as, for example, RXcontrol logic, a voltage detector 126, and a power detector 127.

The target resonator 133 receives electromagnetic energy 130 from thesource resonator 131. For example, the target resonator 133 receivescommunication power or charging power from the source 110 via magneticcoupling with the source resonator 131. Additionally, the targetresonator 133 may receive data from the source 110 using in-bandcommunication or out-band communication(not illustrated in FIG. 1).

The target resonator 133 may receive the initial wireless power that isdetermined based on the change in the temperature of the source 110, thebattery state of the target 120, the change in the amount of powerreceived by the target 120, and/or the change in the temperature of thetarget 120.

The matching network 121 matches an input impedance viewed from thesource 110 to an output impedance viewed from a load. The matchingnetwork 121 may be configured with a combination of a capacitor and aninductor.

The rectification unit 122 generates a DC voltage by rectifying an ACvoltage received from the target resonator 133.

The DC/DC converter 123 adjusts a level of the DC voltage that is outputfrom the rectification unit 122 based on a voltage required by the load.In an example, the DC/DC converter 123 may adjust the level of the DCvoltage output from the rectification unit 122 within a range of 3 volts(V) to 10 V.

The voltage detector 126 detects a voltage of an input terminal of theDC/DC converter 123, and the power detector 127 detects a current and anvoltage of an output terminal of the DC/DC converter 123. The detectedvoltage of the input terminal may be used by the controller 125 tocompute a transmission efficiency of power received from the source 110.The detected current and the detected voltage of the output terminal maybe also used by the RX controller 125 to compute an amount of powertransferred to the load. The TX controller 114 of the source 110 maydetermine an amount of power that needs to be transmitted by the source110 based on a power required by the load and the power transferred tothe load.

When the amount of power transferred to the load computed by thecommunication unit 124 is transmitted to the source 110, the source 110may compute an amount of power that needs to be transmitted to thetarget 120.

The communication unit 124 performs an in-band communication to transmitor receive data using a resonant frequency. During the in-bandcommunication, the RX controller 125 demodulates a received signal bydetecting a signal between the target resonator 133 and therectification unit 122, or detecting an output signal of therectification unit 122.

The RX controller 125 may also adjust an impedance of the targetresonator 133 using the matching network 121 to modulate a signal to betransmitted to the source 110. For example, the RX controller 125 mayincrease the impedance of the target resonator 133 so that a reflectedwave may be detected by the TX controller 114 of the source 110.Depending on whether the reflected wave is detected, the TX controller114 may detect a first value, for example, a binary number “0,” or asecond value, for example, a binary number “1.” For example, when thereflected wave is detected, the TX controller may detect “0”, and whenthe reflected wave is not detected, the TX controller may detect “1”.Alternatively, when the reflected wave is detected, the TX controllermay detect “1”, and when the reflected wave is not detected, the TXcontroller may detect “0”.

The communication unit 124 of the target 120 may transmit a responsemessage to the communication unit 115 of the source 110. For example,the response message may include one or more of: a type of acorresponding target, information about a manufacturer of thecorresponding target, a model name of the corresponding target, abattery type of the corresponding target, a charging scheme of thecorresponding target, an impedance value of a load of the correspondingtarget, information on characteristics of a target resonator of thecorresponding target, information on a frequency band used by thecorresponding target, an amount of power consumed by the correspondingtarget, an identifier (ID) of the corresponding target, information on aversion or a standard of the corresponding target, and any otherinformation regarding the corresponding target.

The communication unit 124 may perform an out-band communication using aseparate communication channel For example, the communication unit 124may include a communication module, such as a ZigBee module, a Bluetoothmodule, or any other communication module known to one of ordinary skillin the art. The communication unit 124 may transmit or receive data 140to or from the source 110 using the out-band communication.

The communication unit 124 may receive a wake-up request message fromthe source 110, and the power detector 127 may detect an amount of powerreceived by the target resonator 133. The communication unit 124 maytransmit, to the source 110, information on the detected amount of thepower. The information on the detected amount of the power may include,for example, an input voltage value and an input current value of therectification unit 122, an output voltage value and an output currentvalue of the rectification unit 122, an output voltage value and anoutput current value of the DC/DC converter 123, and any otherinformation about the detected amount of the power.

FIG. 2 illustrates an example of an apparatus for charge control thatmay be used in a wireless charging system. Hereinafter, the apparatusfor charge control that may be used in the wireless charging system willbe referred to as the charge control apparatus.

Referring to FIG. 2, the charge control apparatus includes a resonator,a switch, a rectifier, a power amplifier, a bidirectional DC/DCconverter, a charging circuit, and a battery.

In this example, the charge control apparatus may operate in atransmitting mode or in a receiving mode. However, the charge controlapparatus is not limited thereto. For instance, in another example, acharge control apparatus may operate only in a transmitting mode, oronly in a receiving mode.

Referring back to FIG. 2, in the receiving mode, the charge controlapparatus may receive power. In the transmitting mode, the chargecontrol apparatus may transmit power.

In addition, the charge control apparatus may operate in a relay mode.In the relay mode, the charge control apparatus may relay or transmit aninput power to transfer the power to another terminal. For example, acompletely charged terminal may operate in the relay mode to transfer aninput power to another terminal.

In the receiving mode, the switch may connect the resonator to therectifier. The resonator may receive power wirelessly from an externalpower supply apparatus through a mutual resonance. The rectifier mayrectify an AC power received from the resonator to a DC power. Thebidirectional DC/DC converter may adjust a voltage level of the DC powerof the rectifier into a charging voltage level of the battery. In thisexample, the voltage level of the DC power is greater than the chargingvoltage level of the battery. Thus, the bidirectional DC/DC convertermay perform a step-down operation to decrease the voltage level. Thebidirectional DC/DC converter may operate as a buck converter.

In the transmitting mode, the switch may connect the resonator to thepower amplifier. A voltage level of power charged in the battery may beamplified to a supply voltage level of the power amplifier through thebidirectional DC/DC converter. As the supply voltage level of the poweramplifier, a voltage greater than or equal to a threshold value may berequired for power transmission via the resonator. The supply voltage ofthe power amplifier may refer to a driving voltage to be used to drivethe power amplifier. For example, 5 V may be applied as the thresholdvalue. However, the threshold value is not limited thereto, and may varybased on application. In this example, the supply voltage level isgreater than the voltage level of the power charged in the battery.Thus, the bidirectional DC/DC converter may perform a step-up operationfor increasing the voltage level. The bidirectional DC/DC converter mayoperate as a boost converter.

In an example, the bidirectional DC/DC converter may have aconfiguration of an integrated DC/DC converter 340 illustrated in FIG.3. In another example, the bidirectional DC/DC converter may include afirst DC/DC converter 440 and a second DC/DC converter 470, asillustrated in FIG. 4.

The charging circuit may refer to a circuit that may be mounted in acharger, or to an electric circuit to be used for charging the battery.The charging circuit may be used in a process of charging the battery inthe receiving mode.

FIGS. 3A and 3B are blocks diagram illustrating an example of anapparatus for charge control.

Referring to FIG. 3A, the charge control apparatus 300 includes aresonator 310, an AC/DC converter 320, a power amplifier 330, anintegrated DC/DC converter 340, and a controller 360. A load 350 may beincluded as a part of the charge control apparatus 300, or maycorrespond to an external apparatus separate from the charge controlapparatus 300.

The charge control apparatus 300 may operate in a transmitting mode or areceiving mode. In the receiving mode, the charge control apparatus 300may receive power. In the transmitting mode, the charge controlapparatus 300 may transmit power.

The resonator 310 may receive an AC power through a mutual resonancewith a wireless power transmitter (not shown), in the receiving mode.The resonator 310 may transmit an AC power amplified by the poweramplifier 330 through a mutual resonance with a wireless power receiver(not shown), in the transmitting mode. The resonator 310 may be used asa resonator configured to receive power, in the receiving mode, and maybe used as a resonator configured to transmit power, in the transmittingmode.

The AC/DC converter 320 may convert an AC power received wirelesslythrough a mutual resonance into a DC power, in the receiving mode. Forexample, the AC/DC converter 320 may operate as a rectifier.

The integrated DC/DC converter 340 may step down a voltage level of theDC power converted by the AC/DC converter 320 to a voltage levelrequired by the load 350 in the receiving mode, and may step up anoutput voltage level of the load 350 to be greater than or equal to asupply voltage level set in the power amplifier 330 in the transmittingmode. For example, when the load 350 corresponds to a portable phone,the voltage level required by the load 350 may be in a range of 3.3 V to3.8 V. The required voltage level may have various values depending on atype of the load 350. In addition, 5 V may be set to be the supplyvoltage level.

The integrated DC/DC converter 340 may operate as a buck converterconfigured to step down a voltage in the receiving mode, and may operateas a boost converter configured to step up a voltage in the transmittingmode.

A third switch unit 380 may connect the AC/DC converter 320 to theintegrated DC/DC converter 340 in the receiving mode. The third switchunit 380 may connect the power amplifier 330 to the integrated DC/DCconverter 340 in the transmitting mode. The third switch unit 380 mayconnect the integrated DC/DC converter 340 to one of the AC/DC converter320 and the power amplifier 330.

The power amplifier 330 may convert the DC voltage stepped up by theintegrated DC/DC converter 340 into an AC voltage based on a resonantfrequency, and may amplify the converted AC voltage, in the transmittingmode. The power amplifier 330 may adjust a degree of the amplificationbased on an amount of power to be transmitted through the resonator 310.The power amplifier 330 may perform an operation of a DC/AC converterthat is configured to convert a DC voltage into an AC voltage using aresonant frequency of the resonator 310.

Referring to FIG. 3A, the integrated DC/DC converter 340 may have thefollowing configuration in order to perform a step-up operation and astep-down operation.

The integrated DC/DC converter 340 includes a first capacitor 341, afirst transistor 342, a second transistor 343, an inductor 344, a secondcapacitor 345, and an output voltage determining unit 346.

The first capacitor 341 may be connected in parallel to at least one ofthe AC/DC converter 320 and the power amplifier 330.

The first transistor 342 may be connected in series to the firstcapacitor 341, and may be of a P-channel metal oxide semiconductor(PMOS) type.

The second transistor 343 may be connected in parallel to the firsttransistor 342, and may be of an N-channel metal oxide semiconductor(NMOS) type.

The inductor 344 may be connected in series to the second transistor343.

The second capacitor 345 may be connected in parallel to the load 350.The second capacitor 345 may be connected in parallel to the inductor344.

Depending on an operation of the output voltage determining unit 346,the integrated DC/DC converter 340 may operate as a buck converter, ormay operate as a boost converter.

The output voltage determining unit 346 may determine a voltage appliedto the second capacitor 345 to be an output voltage of the integratedDC/DC converter 340, in the receiving mode. The output voltagedetermining unit 346 may determine a voltage applied to the firstcapacitor 341 to be the output voltage of the integrated DC/DC converter340, in the transmitting mode.

The output voltage determined by the output voltage determining unit 346may be input into the second transistor 343. The output voltagedetermined by the output voltage determining unit 346 may be input intothe second transistor 343 such that a feedback circuit may be formed. Inthe receiving mode, the voltage applied to the second capacitor 345 maybe input into the second transistor 343 such that a feedback circuit maybe formed. In the transmitting mode, the voltage applied to the firstcapacitor 341 may be input into the second transistor 343 such that afeedback circuit may be formed.

Referring to FIG. 3A, the load 350 includes a first switch unit 351, abattery charger 353, and a battery 355.

The battery charger 353 may charge the battery 355 by storing the DCvoltage stepped down by the integrated DC/DC converter 340.

The battery 355 may be charged by the battery charger 353, in thereceiving mode. For example, using the DC voltage stepped down by theintegrated DC/DC converter 340, the battery 355 may be charged directlyin the receiving mode. Conversely, the battery 355 may transfer the DCvoltage to the integrated DC/DC converter 340, in the transmitting mode.For example, the power stored in the battery 355 may be transmittedwirelessly through the integrated DC/DC converter 340, the poweramplifier 330, and the resonator 310.

The first switch unit 351 may connect the battery charger 353 to thebattery 355, in the receiving mode. The first switch unit 351 may breakthe connection between the battery charger 353 and the battery 355, andmay connect the integrated DC/DC converter 340 to the battery 355, inthe transmitting mode.

For example, the controller 360 may determine a mode of the chargecontrol apparatus 300 as either the receiving mode or the transmittingmode based on a user input. The controller 360 may control the firstswitch unit 351, the second switch unit 370, and the third switch unit380.

In another example, the controller 360 may determine a mode of thecharge control apparatus 300 as either the receiving mode or thetransmitting mode based on an amount of power stored in the load 350.When the amount of power stored in the load 350 is less than or equal toa reference set by a user, the controller 360 may control the chargecontrol apparatus 300 to operate in the receiving mode. When a requestfor power transmission is received from another terminal and the amountof power stored in the load 350 is greater than or equal to a minimumtransmittable reference, the controller may control the charge controlapparatus 300 to operate in the transmitting mode.

The controller 360 may control the third switch unit 380 to adjust theconnection between the AC/DC converter 320 and the integrated DC/DCconverter 340, and the connection between the integrated DC/DC converter340 and the power amplifier 330.

The controller 360 may control an operating time of the first transistor342 based on a difference between a voltage applied to the secondcapacitor 345 and a voltage required by the load 350, in the receivingmode. When the voltage applied to the second capacitor is less than thevoltage required by the load 350, the controller 360 may increase anoperating time, for example a turn-on time, of the first transistor 342.Conversely, when the voltage applied to the second capacitor 345 isgreater than the voltage required by the load 350, the controller 360may reduce the operating time, for example, the turn-on time, of thefirst transistor 342.

The controller 360 may control the operating time of the firsttransistor 345 based on a difference between a voltage applied to thefirst capacitor 341 and a supply voltage set in the power amplifier 330,in the transmitting mode. When the voltage applied to the firstcapacitor 341 is less than the supply voltage set in the power amplifier330, the controller 360 may increase the operating time, for example,the turn-on time, of the first transistor 342. Conversely, when thevoltage applied to the first capacitor 341 is greater than the supplyvoltage set in the power amplifier 330, the controller 360 may reducethe operating time, for example, the turn-on time, of the firsttransistor 342.

A second switch unit 370 may connect the resonator 310 to the AC/DCconverter 320, in the receiving mode. The second switch unit 370 maybreak the connection between the resonator 310 and the AC/DC converter320, and may connect the resonator 310 to the power amplifier 330, inthe transmitting mode.

The controller 360 may determine a mode to be one of the receiving modeand the transmitting mode, based on the amount of the power stored inthe load 350, and may control operations of the first switch unit 351,the second switch unit 370, and the third switch unit 380, based on thedetermined mode.

The controller 360 may determine a mode to be one of the receiving modeand the transmitting mode, based on a user selection, and may controloperations of the first switch unit 351, the second switch unit 370, andthe third switch unit 380, based on the determined mode.

Referring to FIG. 3B, a driving voltage determining unit 347A maydetermine a driving voltage to operate an output voltage determiningunit 346A. The driving voltage determining unit 347A may compare avoltage applied to a second capacitor 345A to a voltage applied to afirst capacitor 341A, and determine a higher voltage to be the drivingvoltage of the output voltage determining unit 346A.

Since the voltage applied to the first capacitor 341A may be greaterthan the voltage applied to the second capacitor 345A in the receivingmode, the voltage applied to the first capacitor 341A may be determinedto be the driving voltage of the output voltage determining unit 346A.

In the transmitting mode, it may take a time for the voltage applied tothe first capacitor 341A to reach the supply voltage set in the poweramplifier 330. Since there may be a transient state, the voltage appliedto the second capacitor 345A may be greater than the voltage applied tothe first capacitor 341A at the beginning of the transmitting mode.Thus, in the beginning of the transmitting mode, the voltage applied tothe second capacitor 345A may be determined to be the driving voltage ofthe output voltage determining unit 346A. Over time, the voltage appliedto the first capacitor 341A may be determined to be the driving voltageof the output voltage determining unit 346A.

The controller 360 may perform an overall control of the charge controlapparatus 300, and may perform functions of the AC/DC converter 320, thepower amplifier 330, and the integrated DC/DC converter 340. The AC/DCconverter 320, the power amplifier 330, and the integrated DC/DCconverter 340 are separately illustrated in FIG. 3 in order to describeeach function separately. Thus, in response to a product beingimplemented, the controller 360 may perform all of the functions, or mayperform a portion of the functions.

FIG. 4 illustrates another example of an apparatus 400 for chargecontrol that may be used in a wireless charging system.

Referring to FIG. 4, the charge control apparatus 400 includes aresonator 410, a first switch unit 420, a rectification unit 430, afirst DC/DC converter 440, a power amplifier 460, a second DC/DCconverter 470, a second switch unit 480, and a controller 490. A load450 may be included as a part of the charge control apparatus 400, ormay correspond to an external apparatus separating from the chargecontrol apparatus 400.

The charge control apparatus 400 may operate in a transmitting mode orin a receiving mode. In the receiving mode, the charge control apparatus400 may receive power. In the transmitting mode, the charge controlapparatus 400 may transmit power.

The resonator 410 may receive an AC power through a mutual resonancewith a wireless power transmitter (not shown), in the receiving mode.The resonator 410 may transmit an AC power amplified by the poweramplifier 460 through a mutual resonance with a wireless power receiver(not shown), in the transmitting mode.

In the transmitting mode, the first switch unit 420 may connect theresonator 410 to the rectification unit 430, in the receiving mode, andmay connect the resonator 410 to the power amplifier 460.

In the receiving mode, the rectification unit 430 may rectify an ACpower received wirelessly through a mutual resonance into a DC power.

Further, in the receiving mode, the first DC/DC converter 440 may stepdown a voltage level of the DC power rectified by the rectifying unit430 to a voltage level required by the load 450.

The second DC/DC converter 470 may step up an output voltage level ofthe load 450 to be greater than or equal to a supply voltage level setin the power amplifier 460, in the transmitting mode.

The first DC/DC converter 440 may operate as a buck converter configuredto step down a voltage in the receiving mode, and the second DC/DCconverter 470 may operate as a boost converter configured to step up avoltage in the transmitting mode. The first DC/DC converter 440 and thesecond DC/DC converter 470 may be mounted on a single module.

The power amplifier 460 may convert the DC voltage stepped up by thesecond DC/DC converter 470 into an AC voltage based on a resonantfrequency, and may amplify the converted AC voltage, in the transmittingmode. The power amplifier 460 may adjust a degree of the amplificationbased on an amount of power to be transmitted through the resonator 410.

The second switch unit 480 may connect the load 450 to the second DC/DCconverter 470, in the transmitting mode. The second switch unit 480 maybreak the connection between the load 450 and the second DC/DC converter470, in the receiving mode.

The controller 490 may control operations of the first switch unit 420and the second switch unit 480, based on the amount of the power storedin the load 450.

The load 450 includes a battery charger 451, and a battery 453.

The battery charger 451 may charge the battery 453 by storing the DCvoltage stepped down by the first DC/DC converter 440. The battery 453may be charged by the battery charger 451 in the receiving mode, and maytransfer the DC voltage to the second DC/DC converter 470 in thetransmitting mode.

The controller 490 may perform an overall control of the charge controlapparatus 400, and may perform functions of the first switch unit 420,the rectification unit 430, the first DC/DC converter 440, the poweramplifier 460, the second DC/DC converter 470, and the second switchunit 480. The first switch unit 420, the rectification unit 430, thefirst DC/DC converter 440, the power amplifier 460, the second DC/DCconverter 470, and the second switch unit 480 are separately illustratedin FIG. 4 in order to describe each function separately. However, aproduct may be implemented such that a controller 490 with or withoutseparate units may perform all of the functions, or may perform aportion of the functions.

FIG. 5 illustrates an example of a wireless charging system.

Referring to FIG. 5, the wireless charging system includes a wirelesspower transmitter 510, a wireless power receiver 515, and an apparatus520 for charge control in the wireless charging system. The wirelesspower receiver 515 may include other devices not illustrated in FIG. 5.

The wireless power transmitter 510 includes an AC/DC converter 511, apower amplifier 513, and a resonator 514. The AC/DC converter 511 mayconvert an AC power received in a wired or wireless manner into a DCpower. The power amplifier 513 may convert the DC power converted by theAC/DC converter 511 into an AC power using a resonant frequency of theresonator 514, and may amplify the AC power based on an amount of powerto be transferred. A mutual resonance may refer to a magnetic resonancebetween the resonator 514 and a resonator 521.

The charge control apparatus 520 includes the resonator 521, an AC/DCconverter 523, a DC/DC converter 525, and a power amplifier 527. Thecharge control apparatus 520 may transfer power to a load 530, and maytransfer power supplied by the load 530 to the wireless power receiver515.

The charge control apparatus 520 may operate as a wireless powerreceiver or a wireless power transmitter.

When the charge control apparatus 520 operates as the wireless powerreceiver, the AC/DC converter 523 may convert an AC power received fromthe resonator 521 into a DC power. The DC/DC converter 525 may convert avoltage level of the DC power to a voltage level required by the load530. In this example, the voltage level of the DC power converted fromthe AC power is greater than the voltage level required by the load 530.Thus, the DC/DC converter 525 may perform a step-down operation. Forexample, a voltage required by the load 530 may refer to a ratedvoltage. The rated voltage may be changed based on a type and capacityof the load 530. For example, a rated voltage of a portable phone may bein a rage of 3.3 V to 3.8 V. The voltage converted to the voltage levelrequired by the load 530 may be transferred to the load 530. The load530 may refer to a battery system, a battery charger, or a battery.

When the charge control apparatus 520 operates as the wireless powertransmitter, the DC/DC converter 525 may convert a voltage level of theDC power supplied by the load 530 to a supply voltage level of the poweramplifier 527. In this example, the voltage level of the DC powersupplied by the load 530 is less than the supply voltage level of thepower amplifier 527. Thus, the DC/DC converter 525 may perform a step-upoperation. The power amplifier 527 may convert the voltage supplied bythe DC/DC converter 525 into an AC voltage using a resonant frequency ofthe resonator 521, and may amplify the power based on an amount of powerto be transferred.

The resonator 521 may transfer the amplified power, through a mutualresonance between the wireless power receiver 515 and the resonator 516.

FIGS. 6 through 8 illustrate various examples of integrated DC/DCconverter which may be used in an apparatus for charge control in awireless charging system.

The integrated DC/DC converter 340 of FIG. 3 may have a structure of theconverter illustrated in FIG. 6. The integrated DC/DC converter 340 mayoperate in both directions, and may perform both an operation of a buckconverter and an operation of a boost converter.

Referring to FIG. 6, a single capacitor may be connected to an input ofthe integrated DC/DC converter 340, and another single capacitor may beconnected to an output of the integrated DC/DC converter 340. Aninductor may be connected to the input and output of the integratedDC/DC converter 340. A V_(OUT) determining unit configured to select anoutput voltage may be provided. When the integrated DC/DC converter 340operates as the buck converter, a capacitor C_(A) may operate as anoutput capacitor of an AC/DC converter, and a capacitor C_(B) mayoperate as an output capacitor of the integrated DC/DC converter 340.When the integrated DC/DC converter 340 operates as the boost converter,the capacitor C_(A) may operate as an output capacitor of the integratedDC/DC converter 340, and the capacitor C_(B) may operate as an inputcapacitor of the integrated DC/DC converter 340. When a single powertransistor M_(P) and a single power transistor M_(N) are used, and asingle external inductor is used, a size of the entire system may bereduced greatly.

Referring to FIG. 7, when the integrated DC/DC converter 340 operates asthe wireless power receiver, the integrated DC/DC converter 340 mayperform a role of a buck converter.

The buck converter may be configured to generate a stable outputvoltage, irrespective of a change in an input voltage. Accordingly, avoltage of V_(B) may be selected by a V_(OUT) determining unit, and astable output voltage may be generated by an operation of a controller.The controller may control a feedback flow, and may perform an operationof a driving buffer.

The integrated DC/DC converter 340 may generate a voltage V_(IND) havinga voltage V_(IN) and a ground voltage of 0 V, regularly, by a switchingoperation of a PMOS transistor M_(P) and an NMOS transistor M_(N). Theintegrated DC/DC converter 340 may generate a voltage V_(OUT) byperforming LC-filtering with respect to the voltage V_(IND) by aninductor and a capacitor. The voltage V_(OUT) may have an average valueof the voltage V_(IND). Since the voltage V_(OUT) may have the averagevalue of the voltage V_(IND) having the voltage V_(IN) and the voltageof 0 V, regularly, the voltage V_(OUT) may be lower than the voltageV_(IN) at all times.

When the voltage V_(B) is less than a voltage predetermined by a user,the controller may increase a time for which the voltage V_(IND) has thevoltage V_(IN), by increasing a time during which the PMOS transistorM_(P) is turned on, thereby controlling a feedback loop so that theLC-filtered voltage V_(OUT) may increase. The controller may include adriving buffer configured to drive the power transistors M_(P) andM_(N).

Referring to FIG. 8, when the integrated DC/DC converter 340 operates asthe wireless power transmitter, the integrated DC/DC converter 340 mayperform a role of a boost converter.

When the integrated DC/DC converter 340 operates as the boost converter,an output voltage may correspond to the voltage of a V_(A) node, aV_(OUT) determining unit may select V_(A), and may input the V_(A) intoa controller.

The integrated DC/DC converter 340 may turn on an NMOS transistor M_(N)to store energy in an inductor, and may turn on a PMOS transistor M_(P)to transfer energy of the inductor and V_(IN) to V_(OUT). In thisexample, the V_(OUT) may have a voltage greater than a voltage of theV_(IN) at all times. When V_(A) is less than a voltage predetermined bya user, the controller may increase a time during which the PMOStransistor M_(P) is turned ON, thereby increasing a time during whichboth the V_(IN) and the energy of the inductor are transferred to theV_(OUT).

FIG. 9 illustrates still another example of an apparatus for chargecontrol that may be used in a wireless charging system.

Referring to FIG. 9, in a receiving mode, a resonator may be connectedto an AC/DC converter by a switch. In a transmitting mode, the resonatormay be connected to a power amplifier by the switch.

The AC/DC converter may be configured to convert an AC voltage receivedfrom the resonator into a stable DC voltage and supply the DC voltage toan input of an integrated DC/DC converter. The power amplifier may beconfigured to amplify an output power of the integrated DC/DC converterto a power required for a mutual resonance.

FIG. 10 illustrates yet another example of an apparatus for chargecontrol that may be used in a wireless charging system.

When compared to FIG. 9, when a battery charger is provided, a switch toconnect the battery charger directly to an integrated DC/DC convertermay be required for receiving a power supplied by a battery, in atransmitting mode.

FIG. 11 illustrates an example of a method for charge control in awireless charging system.

Referring to FIG. 11, in 1110, an apparatus for charge control in thewireless charging system determines whether to operate in a receivingmode. For example, the charge control apparatus may receive powerwirelessly using a resonator in the receiving mode, and may transferpower wirelessly using the resonator in a transmitting mode. As anexample, the charge control apparatus may determine whether to operatein the receiving mode, based on an amount of power stored in a battery.

In 1120, the charge control apparatus receives an AC power through theresonator when the charge control apparatus operates in the receivingmode. For example, the charge control apparatus may receive the AC powerwirelessly through a mutual resonance.

In 1130, the charge control apparatus converts the AC power into a DCpower. For example, the charge control apparatus may rectify the ACpower.

In 1140, the charge control apparatus steps down a voltage level of theDC power to a voltage level required for charging a load, using anintegrated DC/DC converter.

In 1150, the charge control apparatus transfers the stepped down voltageto the load.

In 1160, the charge control apparatus steps up a DC output voltage ofthe load to be greater than or equal to a DC supply voltage set in apower amplifier, using the integrated DC/DC converter.

In 1170, the charge control apparatus converts the DC voltage into an ACvoltage, using the power amplifier, and amplifies the AC voltage basedon an amount of power to be transferred through a mutual resonance.

In 1180, the charge control apparatus transmits the AC power to awireless power receiver, through the mutual resonance of the resonator.

When the charge control apparatus is implemented, by greatly reducing asize of an integrated circuit and an external component, a size of theentire chip may be reduced exceedingly. Accordingly, the charge controlapparatus may be applied in actuality by reducing a form factor, forexample, a size, when a transmitting (TX) system and a receiving (RX)system are mounted in a single device in order to enable bidirectionalwireless power transmission.

The charge control apparatus may be applied to all systems configured tocharge other devices using a charged device wirelessly and thus, theutility of the charge control apparatus may be considerably great. Forexample, the charge control apparatus may be applied to an applicationfor charging a cellular phone wirelessly in a potable tablet personalcomputer (PC) capable of wireless charging, and may also be applied forcharging all devices requiring a power supply in an electrical vehicle(EV). In addition, the charge control apparatus may also be applied to aportable charger, and the like for charging a device inserted into ahuman body.

FIGS. 12A through 14B illustrates examples of applications in which anapparatus for charge control may be used in a wireless charging system.

FIG. 12A illustrates wireless power charging between a pad 1210 and amobile terminal 1220, and FIG. 12B illustrates wireless power chargingbetween pads 1230 and 1240 and hearing aids 1250 and 1260.

Referring to FIG. 12A, a charge control apparatus may be mounted on, orinstalled within the pad 1210. Conversely, a charge control apparatusmay be mounted on or installed in the mobile terminal 1220. In anotherexample, the charge control apparatus may be disposed in a vicinity ofthe pad 1210 and the mobile terminal 1220. The pad 1210 may be awireless power transmitter that charges the single mobile terminal 1220.

Referring to FIG. 12B, two hearing aids 1250 are mounted on the pad 1230and the pad 1240, respectively. The hearing aid 1250 may correspond to ahearing aid for a left ear, and the hearing aid 1260 may correspond to ahearing aid for a right ear. Two charge control apparatuses may bemounted on or installed within the hearing aid 1250 and the hearing aid1260, respectively. In another example, the charge control apparatus maybe provided in a vicinity of both the hearing aids 1250, 1260 and thepads 1230, 1240.

FIG. 13A illustrates wireless power charging between a mobile terminal1310 and a tablet PC 1320, and FIG. 13B illustrates wireless powercharging between a mobile terminal 1330 and a mobile terminal 1340. FIG.13C illustrates wireless power charging between a mobile terminal 1350and a mobile terminal 1360 via a charge control apparatus 1370.

Referring to FIG. 13A, a charge control apparatus may be mounted on orinstalled within the mobile terminal 1310. A charge control apparatusmay be mounted on or installed within the tablet PC 1320. In anotherexample, the charge control apparatus may be provided in a vicinity ofthe mobile terminal 1310 and the tablet PC 1320. The mobile terminal1310 and the tablet PC 1320 may exchange power wirelessly.

Referring to FIG. 13B, a charge control apparatus may be mounted on orinstalled within the mobile terminal 1330. A charge control apparatusmay be mounted on or installed within the mobile terminal 1340. Themobile terminal 1330 and the mobile terminal 1340 may exchange powerwirelessly.

Referring to FIG. 13C, a mobile terminal 1350 and a mobile terminal 1360may be charged via a charge control apparatus 1370 that is implementedseparately. The charge control apparatus 1370 may include a batterysystem, a battery charger, or a battery 1380. The charge controlapparatus 1370 may receive power wirelessly from the mobile terminal1350, store the power in the battery 1380, and transmit the powerwirelessly to the mobile terminal 1360. The charge control apparatus1370 may, for example, have a structure of a charge control apparatusillustrated in FIG. 5.

FIG. 14A illustrates wireless power charging between an electronicdevice 1410 inserted into a human body and a mobile device 1420, andFIG. 14B illustrates wireless power charging between a hearing aid 1430and a mobile terminal 1440.

Referring to FIG. 14A, a charge control apparatus may be mounted on orinstalled within the mobile terminal 1420. A charge control apparatusmay be mounted on or installed within the electronic device 1410. Theelectronic device 1410 may be charged by receiving power from the mobileterminal 1420.

Referring to FIG. 14B, a charge control apparatus may be mounted on orinstalled within the mobile terminal 1440. A charge control apparatusmay be mounted on or installed within the hearing aid 1430. The hearingaid 1430 may be charged by receiving power from the mobile terminal1430. In addition to the hearing aid 1430, low-power electronic devices,for example, a Bluetooth headset may be charged by receiving power fromthe mobile device 1440.

FIGS. 15A through 17B illustrate distribution of magnetic field inexamples of resonators. The resonator illustrated in FIGS. 15A through17B may be, for example, a source resonator or a target resonator. Forexample, the resonators illustrated in FIGS. 15A through 17B may beapplied to the resonators of FIGS. 1 through 14B.

FIG. 15A illustrates the distribution of magnetic field in a feeder.When a resonator receives power supplied through a separate feeder,magnetic fields may form in both the feeder and the resonator.

Referring to FIG. 15A, a magnetic field 1530 may be formed as inputcurrent flows into a feeder 1510. A direction 1531 of the magnetic field1530 within the feeder 1510 may have a phase that is opposite to a phaseof a direction 1533 of the magnetic field 1530 outside the feeder 1510.The magnetic field 1530 formed by the feeder 1510 may induce a currentto form inside a resonator 1520. The direction of the induced currentmay be opposite to a direction of the input current.

Due to the induced current, a magnetic field 1540 may form in theresonator 1520. Directions of a magnetic field formed due to inducedcurrent in all positions of the resonator 1520 may be the same.Accordingly, a direction 1541 of the magnetic field 1540 formed by theresonator 1520 may have the same phase as a direction 1543 of themagnetic field 1540 formed by the resonator 1520.

Thus, when the magnetic field 1530 formed by the feeder 1510 and themagnetic field 1540 formed by the resonator 1520 are combined, strengthof the total magnetic field may decrease within the feeder 1510,however, the strength may increase outside the feeder 1510. In anexample in which power is supplied to the resonator 1520 through thefeeder 1510 configured as illustrated in FIG. 15A, the strength of thetotal magnetic field may decrease in the center of the resonator 1520,but may increase outside the resonator 1520. In another example in whicha magnetic field is randomly distributed in the resonator 1520, it maybe difficult to perform impedance matching because an input impedancemay frequently vary. Additionally, when the strength of the totalmagnetic field is increased, an efficiency of wireless powertransmission may be increased. Conversely, when the strength of thetotal magnetic field is decreased, the efficiency for wireless powertransmission may be reduced. Accordingly, the power transmissionefficiency may be reduced on average.

FIG. 15B illustrates an example of a structure of a wireless powertransmitter in which a resonator 1550 and a feeder 1560 have a commonground. The resonator 1550 includes a capacitor 1551. The feeder 1560may receive an input of a radio frequency (RF) signal via a port 1561.

For example, when the RF signal is input to the feeder 1560, inputcurrent may be generated in the feeder 1560. The input current flowingin the feeder 1560 may cause a magnetic field to form, and the magneticfield may generate a current in the resonator 1550 by induction.Additionally, another magnetic field may be formed due to the inducedcurrent flowing in the resonator 1550. In this example, a direction ofthe input current flowing in the feeder 1560 may have a phase oppositeto a phase of a direction of the induced current flowing in theresonator 1550. Accordingly, in a region between the resonator 1550 andthe feeder 1560, a direction 1571 of the magnetic field formed due tothe input current may have the same phase as a direction 1573 of themagnetic field formed due to the induced current; thus, the strength ofthe total magnetic field may increase. Conversely, within the feeder1560, a direction 1581 of the magnetic field formed due to the inputcurrent may have a phase opposite to a phase of a direction 1583 of themagnetic field formed due to the induced current, and thus the strengthof the total magnetic field may decrease. Therefore, the strength of thetotal magnetic field may decrease in the center of the resonator 1550,but may increase outside the resonator 1550.

The feeder 1560 may determine an input impedance by adjusting aninternal area of the feeder 1560. The input impedance refers to animpedance viewed in a direction from the feeder 1560 to the resonator1550. When the internal area of the feeder 1560 is increased, the inputimpedance may be increased. Conversely, when the internal area of thefeeder 1560 is reduced, the input impedance may be reduced. Because themagnetic field is randomly distributed in the resonator 1550 despite areduction in the input impedance, a value of the input impedance mayvary based on a location of a target device. Accordingly, a separatematching network may be required to match the input impedance to anoutput impedance of a power amplifier. For example, when the inputimpedance is increased, a separate matching network may be used to matchthe increased input impedance to a relatively low output impedance.

FIG. 16A illustrates an example of a wireless power transmitter.

Referring to FIG. 16A, the wireless power transmitter includes aresonator 1610, and a feeding unit 1620. The resonator 1610 may furtherinclude a capacitor 1611. The feeding unit 1620 may be electricallyconnected to both ends of the capacitor 1611.

FIG. 16B illustrates structures of the wireless power transmitterillustrated in FIG. 16A. The resonator 1610 may include a firsttransmission line, a first conductor 1641, a second conductor 1642, andat least one first capacitor 1650.

The first capacitor 1650 may be inserted in series between a firstsignal conducting portion 1631 and a second signal conducting portion1632 in the first transmission line, and an electric field may beconfined within the first capacitor 1650. For example, the firsttransmission line may include at least one conductor in an upper portionof the first transmission line, and may also include at least oneconductor in a lower portion of the first transmission line. Current mayflow through the at least one conductor disposed in the upper portion ofthe first transmission line. The at least one conductor disposed in thelower portion of the first transmission line may be electricallygrounded. For example, a conductor disposed in an upper portion of thefirst transmission line may be separated into and referred to as thefirst signal conducting portion 1631 and the second signal conductingportion 1632. A conductor disposed in a lower portion of the firsttransmission line may be referred to as a first ground conductingportion 1633.

Referring to FIG. 16B, the resonator 1610 may have a substantiallytwo-dimensional (2D) structure. The first transmission line may includethe first signal conducting portion 1631 and the second signalconducting portion 1632 in the upper portion of the first transmissionline. In addition, the first transmission line may include the firstground conducting portion 1633 in the lower portion of the firsttransmission line. The first signal conducting portion 1631 and thesecond signal conducting portion 1632 may face the first groundconducting portion 1633. Current may flow through the first signalconducting portion 1631 and the second signal conducting portion 1632.

Additionally, one end of the first signal conducting portion 1631 may beelectrically connected (i.e., shorted) to the first conductor 1641, andanother end of the first signal conducting portion 1631 may be connectedto the first capacitor 1650. One end of the second signal conductingportion 1632 may be shorted to the second conductor 1642, and anotherend of the second signal conducting portion 1632 may be connected to thefirst capacitor 1650. Accordingly, the first signal conducting portion1631, the second signal conducting portion 1632, the first groundconducting portion 1633, and the conductors 1641 and 1642 may beconnected to each other, so that the resonator 1610 may have anelectrically closed-loop structure. The term “loop structure” mayinclude, for example, a polygonal structure such as a rectangularstructure, octagonal structure and the like, and partially or entirelyround structure, such as a circular structure, an elliptical structureand the like. “Having a loop structure” may indicate that the circuit iselectrically closed.

The first capacitor 1650 may be inserted into an intermediate portion ofthe first transmission line. For example, the first capacitor 1650 maybe inserted into a space between the first signal conducting portion1631 and the second signal conducting portion 1632. The first capacitor1650 may be configured as a lumped element, a distributed element, andthe like. For example, a capacitor configured as a distributed elementmay include zigzagged conductor lines and a dielectric material that hasa high permittivity positioned between the zigzagged conductor lines.

When the first capacitor 1650 is inserted into the first transmissionline, the resonator 1610 may have a characteristic of a metamaterial. Ametamaterial refers to a material having a predetermined electricalproperty that is not discovered in nature, and thus, may have anartificially designed structure. An electromagnetic characteristic ofthe materials existing in nature may have a unique magnetic permeabilityor a unique permittivity. Most materials may have a positive magneticpermeability or a positive permittivity.

In the case of most materials found in nature, a right hand rule may beapplied to an electric field, a magnetic field, and a pointing vector;thus, the corresponding materials are referred to as right handedmaterials (RHMs). However, a metamaterial has a magnetic permeability ora permittivity absent in nature, and may be classified into an epsilonnegative (ENG) material, a mu negative (MNG) material, a double negative(DNG) material, a negative refractive index (NRI) material, aleft-handed (LH) material, and the like, based on a sign of thecorresponding permittivity or magnetic permeability.

When a capacitance of the first capacitor 1650 inserted as the lumpedelement is appropriately set, the resonator 1610 may have thecharacteristic of the metamaterial. Because the resonator 1610 may havea negative magnetic permeability by appropriately adjusting thecapacitance of the first capacitor 1650, the resonator 1610 may also bereferred to as an MNG resonator. Various criteria may be applied todetermine the amount of capacitance of the first capacitor 1650. Forexample, the various criteria may include a criterion for enabling theresonator 1610 to have the characteristic of the metamaterial, acriterion for enabling the resonator 1610 to have a negative magneticpermeability in a target frequency, a criterion for enabling theresonator 1610 to have a zeroth order resonance characteristic in thetarget frequency, and the like. Based on at least one criterion amongthe aforementioned criteria, the capacitance of the first capacitor 1650to be used may be determined.

The resonator 1610, also referred to as the MNG resonator 1610, may havea zeroth order resonance characteristic of having, as a resonancefrequency, a frequency when a propagation constant is “0”. Because theresonator 1610 may have a zeroth order resonance characteristic, theresonance frequency may be independent with respect to a physical sizeof the MNG resonator 1610. By appropriately designing or determining theconfiguration of the first capacitor 1650, the MNG resonator 1610 maysufficiently change the resonance frequency without changing thephysical size of the MNG resonator 1610.

In a near field, for instance, the electric field may be concentrated onthe first capacitor 1650 inserted into the first transmission line.Accordingly, due to the first capacitor 1650, the magnetic field maybecome dominant in the near field. The MNG resonator 1610 may have arelatively high Q-argument using the first capacitor 1650 of the lumpedelement; thus, it may be possible to enhance an efficiency of powertransmission. For example, the Q-argument may indicate a level of anohmic loss or a ratio of a reactance with respect to a resistance in thewireless power transmission. The efficiency of the wireless powertransmission may increase according to an increase in the Q-argument.

Although not illustrated in FIG. 16B, a magnetic core may be furtherprovided to pass through the MNG resonator 1610. The magnetic core mayperform a function of increasing a power transmission distance.

Referring to FIG. 16B, the feeding unit 1620 may include a secondtransmission line, a third conductor 1671, a fourth conductor 1672, afifth conductor 1681, and a sixth conductor 1682.

The second transmission line may include a third signal conductingportion 1661 and a fourth signal conducting portion 1662 in an upperportion of the second transmission line. In addition, the secondtransmission line may include a second ground conducting portion 1663 ina lower portion of the second transmission line. The third signalconducting portion 1661 and the fourth signal conducting portion 1662may face the second ground conducting portion 1663. Current may flowthrough the third signal conducting portion 1661 and the fourth signalconducting portion 1662.

Additionally, one end of the third signal conducting portion 1661 may beshorted to the third conductor 1671, and another end of the third signalconducting portion 1661 may be connected to the fifth conductor 1681.One end of the fourth signal conducting portion 1662 may be shorted tothe fourth conductor 1672, and another end of the fourth signalconducting portion 1662 may be connected to the sixth conductor 1682.The fifth conductor 1681 may be connected to the first signal conductingportion 1631, and the sixth conductor 1682 may be connected to thesecond signal conducting portion 1632. The fifth conductor 1681 and thesixth conductor 1682 may be connected in parallel to both ends of thefirst capacitor 1650. In this example, the fifth conductor 1681 and thesixth conductor 1682 may be used as input ports to receive an RF signalas an input.

Accordingly, the third signal conducting portion 1661, the fourth signalconducting portion 1662, the second ground conducting portion 1663, thethird conductor 1671, the fourth conductor 1672, the fifth conductor1681, the sixth conductor 1682, and the resonator 1610 may be connectedto each other, so that the resonator 1610 and the feeding unit 1620 mayhave an electrically closed-loop structure. The term “loop structure”may include, for example, a polygonal structure such as a rectangularstructure, an octagonal structure and the like, or a partially orentirely round structure such as a circular structure, an ellipticalstructure and the like. When an RF signal is received via the fifthconductor 1681 or the sixth conductor 1682, input current may flow inthe feeding unit 1620 and the resonator 1610, a magnetic field may formdue to the input current. The magnetic field may generate a current inthe resonator 1610 by induction. A direction of the input currentflowing in the feeding unit 1620 may be the same as a direction of theinduced current flowing in the resonator 1610. Thus, strength of thetotal magnetic field may increase in the center of the resonator 1610,but may decrease outside the resonator 1610.

An input impedance may be determined based on an area of a regionbetween the resonator 1610 and the feeding unit 1620; accordingly, aseparate matching network used to match the input impedance to an outputimpedance of a power amplifier may not be required. For example, evenwhen the matching network is used, the input impedance may be determinedby adjusting a size of the feeding unit 1620; thus, a structure of thematching network may be simplified. The simplified structure of thematching network may minimize a matching loss of the matching network.

The second transmission line, the third conductor 1671, the fourthconductor 1672, the fifth conductor 1681, and the sixth conductor 1682may form the same structure as the resonator 1610.

FIG. 17A illustrates an example of a distribution of a magnetic fieldwithin a resonator based on feeding of a feeding unit. In other words,FIG. 17A more briefly illustrates the resonator 1610 and the feedingunit 1620 of FIG. 16A, and FIG. 17B illustrates one equivalent circuitof a feeding unit 1740, and one equivalent circuit of a resonator 1750.

A feeding operation may refer to supplying power to a source resonatorin wireless power transmission, or refer to supplying AC power to arectification unit in a wireless power transmission. FIG. 17Aillustrates a direction of input current flowing in the feeding unit,and a direction of induced current induced in the source resonator.Additionally, FIG. 17A illustrates a direction of a magnetic fieldformed due to the input current of the feeding unit, and a direction ofa magnetic field formed due to the induced current of the sourceresonator.

Referring to FIG. 17A, the fifth conductor 1681 or the sixth conductor1682 of the feeding unit 1620 may be used as an input port 1710. Theinput port 1710 may receive an RF signal as an input. The RF signal maybe output from a power amplifier. The power amplifier may increase ordecrease an amplitude of the RF signal based on a demand by a targetdevice. The RF signal received by the input port 1710 may be displayedin the form of input current flowing in the feeding unit. The inputcurrent may flow in a clockwise direction in the feeding unit, along atransmission line of the feeding unit. The fifth conductor of thefeeding unit may be electrically connected to the resonator. Forexample, the fifth conductor may be connected to a first signalconducting portion of the resonator. Accordingly, the input current mayflow in the resonator, as well as, in the feeding unit. The inputcurrent may flow in a counterclockwise direction in the resonator. Theinput current flowing in the resonator may cause a magnetic field toform. The magnetic field may generate current in the resonator byinduction. The induced current may flow in a clockwise direction in theresonator. For example, the induced current may transfer energy to acapacitor of the resonator, and a magnetic field may form due to theinduced current. In this example, the input current flowing in thefeeding unit and the resonator is indicated by a solid line of FIG. 17A,and the induced current flowing in the resonator is indicated by adotted line of FIG. 17A.

A direction of a magnetic field formed due to a current may bedetermined based on the right hand rule. Referring to FIG. 17A, withinthe feeding unit, a direction 1721 of a magnetic field formed due to theinput current flowing in the feeding unit may be identical to adirection 1723 of a magnetic field formed due to the induced currentflowing in the resonator. Accordingly, the strength of the totalmagnetic field may increase within the feeding unit.

In a region between the feeding unit and the resonator, a direction 1733of a magnetic field formed due to the input current flowing in thefeeding unit has a phase opposite to a phase of a direction 1731 of amagnetic field formed due to the induced current flowing in the sourceresonator, as illustrated in FIG. 17A. Accordingly, the strength of thetotal magnetic field may decrease in the region between the feeding unitand the resonator.

In general, a strength of a magnetic field decreases in the center of aresonator with the loop structure, and increases outside the resonator.However, referring to FIG. 17A, the feeding unit may be electricallyconnected to both ends of a capacitor of the resonator, and accordinglythe induced current of the resonator may flow in the same direction asthe input current of the feeding unit. Since the induced current of theresonator flows in the same direction as the input current of thefeeding unit, the strength of the total magnetic field may increasewithin the feeding unit, and may decrease outside the feeding unit. As aresult, the strength of the total magnetic field may increase in thecenter of the resonator with the loop structure, and may decreaseoutside the resonator, due to the feeding unit. Thus, the strength ofthe total magnetic field may be equalized within the resonator.

The power transmission efficiency for transferring a power from thesource resonator to a target resonator may be in proportion to thestrength of the total magnetic field formed in the source resonator. Inother words, when the strength of the total magnetic field increases inthe center of the resonator, the power transmission efficiency may alsoincrease.

Referring to FIG. 17B, the feeding unit 1740 and the resonator 1750 maybe expressed as equivalent circuits. An example of an input impedanceZin viewed in a direction from the feeding unit 1740 to the resonator1750 may be computed, as given in Equation 1.

$\begin{matrix}{Z_{i\; n} = \frac{\left( {\omega \; M} \right)^{2}}{Z}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In Equation 1, M denotes a mutual inductance between the feeding unit1740 and the resonator 1750, to denotes a resonance frequency betweenthe feeding unit 1740 and the resonator 1750, and Z denotes an impedanceviewed in a direction from the resonator 1750 to a target device. Theinput impedance Zin may be in proportion to the mutual inductance M.Accordingly, the input impedance Zin may be controlled by adjusting themutual inductance M. The mutual inductance M may be adjusted based on anarea of a region between the feeding unit 1740 and the resonator 1750.The area of the region between the feeding unit 1740 and the resonator1750 may be adjusted based on a size of the feeding unit 1740.Accordingly, the input impedance Zin may be determined based on the sizeof the feeding unit 1740, and thus a separate matching network may notbe required to perform impedance matching with an output impedance of apower amplifier.

In a target resonator and a feeding unit that are included in a wirelesspower receiver, a magnetic field may be distributed as illustrated inFIG. 17A. For example, the target resonator may receive wireless powerfrom a source resonator through magnetic coupling. Due to the receivedwireless power, induced current may be generated in the targetresonator. A magnetic field formed due to the induced current in thetarget resonator may cause another induced current to be generated inthe feeding unit. In this example, when the target resonator isconnected to the feeding unit as illustrated in FIG. 17A, the inducedcurrent generated in the target resonator may flow in the same directionas the induced current generated in the feeding unit. Thus, the strengthof the total magnetic field may increase within the feeding unit, butmay decrease in a region between the feeding unit and the targetresonator.

FIG. 18 illustrates an example of an electric vehicle charging system.

Referring to FIG. 18, an electric vehicle charging system 1800 includesa source system 1810, a source resonator 1820, a target resonator 1830,a target system 1840, and an electric vehicle battery 1850. Theelectronic vehicle charging system 1800 may include an apparatus forcharge control during a charging operation between the electric vehiclebattery 1850 and the source system 1810.

The electric vehicle charging system 1800 may have a similar structureto the wireless charging system illustrated in FIG. 1. The source system1810 and the source resonator 1820 in the electric vehicle chargingsystem 1800 may function as a source. The target resonator 1830 and thetarget system 1840 in the electric vehicle charging system 1800 mayfunction as a target.

The source system 1810 may include a variable SMPS, a power amplifier, amatching network, a controller, and a communication unit, similarly tothe source 110 illustrated in FIG. 1. The target system 1840 may includea matching network, a rectification unit, a DC/DC converter, acommunication unit, and a controller, similarly to the target 180illustrated in FIG. 1.

The electric vehicle battery 1850 may be charged by the target system1840.

The electric vehicle charging system 1800 may use a resonant frequencyin a band of a few KHz to tens of MHz to transmit power wirelessly.

The source system 1810 may generate power, based on a type of chargingvehicle, a capacity of a battery, and a charging state of a battery, andmay supply the generated power to the target system 1840.

The source system 1810 may control the source resonator 1820 and thetarget resonator 1830 to be aligned. For example, when the sourceresonator 1820 and the target resonator 1830 are not aligned, thecontroller of the source system 1810 may transmit a message to thetarget system 1840, and may control alignment between the sourceresonator 1820 and the target resonator 1830.

For example, when the target resonator 1830 is not located in a positionenabling maximum magnetic resonance, the source resonator 1820 and thetarget resonator 1830 may not be aligned. When a vehicle does not stopaccurately, the source system 1810 may induce a position of the vehicleto be adjusted, and may control the source resonator 1820 and the targetresonator 1830 to be aligned. In another example, the position of thesource resonator 1820 may be adjusted to align the source resonator 1820to the target resonator 1830 of the vehicle.

The source system 1810 and the target system 1840 may transmit orreceive an ID of a vehicle, or may exchange various messages, throughcommunication.

The descriptions of examples of apparatus for charge control illustratedin FIGS. 2 through 17B may be applied to the electric vehicle chargingsystem 1800. For example, the source system 1810 may include anapparatus for charge control. In another example, the target system 1840of the electric vehicle may include an apparatus for charge control.Because more power is required to charge an electric vehicle thanconsumer electronic products, the electric vehicle charging system 1800may use a resonant frequency in a band of a few KHz to tens of MHz, andmay transmit power that is equal to or higher than tens of watts tocharge the electric vehicle battery 1850.

Described above is an example of an apparatus for charge control in awireless charging system, the apparatus including an alternatingcurrent-to-direct current (AC/DC) converter configured to convert an ACpower received wirelessly through a mutual resonance into a DC power, ina receiving mode, an integrated DC-to-DC (DC/DC) converter configured tostep down a voltage level of the DC power to a voltage level required bya load in the receiving mode, and to step up an output voltage level ofthe load to be greater than or equal to a supply voltage level set in apower amplifier in a transmitting mode, and the power amplifierconfigured to convert the DC voltage stepped up by the integrated DC/DCconverter into an AC voltage based on a resonant frequency, and toamplify the converted AC voltage, in the transmitting mode.

The integrated DC/DC converter may include a first capacitor connectedin parallel to at least one of the AC/DC converter and the poweramplifier, a second capacitor connected in parallel to the load, a firsttransistor of a P-channel metal oxide semiconductor (PMOS) type, thefirst transistor connected in series to the first capacitor, a secondtransistor of an N-channel metal oxide semiconductor (NMOS) type, thesecond transistor connected in parallel to the first transistor, aninductor connected in series to the second transistor, and an outputvoltage determining unit configured to determine a voltage applied tothe second capacitor to be an output voltage of the integrated DC/DCconverter in the receiving mode, and to determine a voltage applied tothe first capacitor to be an output voltage of the integrated DC/DCconverter in the transmitting mode.

The apparatus may include a controller configured to activate thereceiving mode by connecting the AC/DC converter to the integrated DC/DCconverter in order to charge the load, and to activate the transmittingmode by connecting the integrated DC/DC converter to the power amplifierin order to transmit power stored in the load, based on an amount ofpower stored in the load. Here, the receiving mode and the transmittingmode may not be activated simultaneously.

The controller may be configured to connect the first transistor and thesecond transistor to the second capacitor for the voltage applied to thesecond capacitor to be fed back to the first transistor and the secondtransistor in the receiving mode.

The controller may be configured to connect the first transistor and thesecond transistor to the first capacitor for the voltage applied to thefirst capacitor to be fed back to the first transistor and the secondtransistor in the transmitting mode.

The load may include a battery charger configured to charge a battery bystoring the DC voltage stepped down by the integrated DC/DC converter,the battery configured to be charged by the battery charger in thereceiving mode, and to transfer a DC voltage to the integrated DC/DCconverter in the transmitting mode, and a first switch unit configuredto connect the battery charger to the battery in the receiving mode, andto break the connection between the battery charger and the battery andconnect the integrated DC/DC converter to the battery in thetransmitting mode.

The apparatus may further include a resonator configured to receive theAC power through a mutual resonance with a wireless power transmitter inthe receiving mode, and to transmit the AC power amplified by the poweramplifier through a mutual resonance with a wireless power receiver inthe transmitting mode.

The apparatus may further include a second switch unit configured toconnect the resonator to the AC/DC converter in the receiving mode, andto break the connection between the resonator and the AC/DC converterand connect the resonator to the power amplifier in the transmittingmode.

In another example, there is provided an apparatus for charge control ina wireless charging system, the apparatus including a rectification unitconfigured to convert an AC power received wirelessly through a mutualresonance into a DC power, in a receiving mode, a first DC/DC converterconfigured to step down a voltage level of the DC power to a voltagelevel required by a load in the receiving mode, a second DC/DC converterconfigured to step up an output voltage level of the load to be greaterthan or equal to a supply voltage level set in a power amplifier in atransmitting mode, and the power amplifier configured to convert the DCvoltage stepped up by the second DC/DC converter into an AC voltagebased on a resonant frequency, and to amplify the converted AC voltage,in the transmitting mode.

The apparatus may further include a resonator configured to receive theAC power through a mutual resonance with a wireless power transmitter inthe receiving mode, and to transmit the AC power amplified by the poweramplifier through a mutual resonance with a wireless power receiver inthe transmitting mode, a first switch unit configured to connect theresonator to the rectification unit in the receiving mode, and toconnect the resonator to the power amplifier in the transmitting mode, asecond switch unit configured to connect the load to the second DC/DCconverter in the transmitting mode, and a controller configured tocontrol operations of the first switch unit and the second switch unit,based on an amount of power stored in the load.

The load may include a battery charger configured to charge a battery bystoring the DC voltage stepped down by the first DC/DC converter, andthe battery configured to be charged by the battery charger in thereceiving mode, and to transfer a DC voltage to the second DC/DCconverter in the transmitting mode.

In still another example, there is provided a method for charge controlin a wireless charging system, the method including converting an ACpower received wirelessly through a mutual resonance into a DC power, ina receiving mode, stepping down a voltage level of the DC power to avoltage level required by a load, using an integrated DC/DC converter inthe receiving mode, stepping up an output voltage level of the load tobe greater than or equal to a supply voltage level set in a poweramplifier, using the integrated DC/DC converter in a transmitting mode,and converting the stepped down DC voltage into an AC voltage based on aresonant frequency, and amplifying the converted AC voltage, in thetransmitting mode.

The method may further include determining one of the receiving mode andthe transmitting mode for an apparatus for charge control in a wirelesscharging system, based on an amount of power stored in the load.

The stepping down may include determining a voltage applied to the loadto be an output voltage of the integrated DC/DC converter in thereceiving mode.

The stepping up may include determining a voltage applied to the poweramplifier to be an output voltage of the integrated DC/DC converter inthe transmitting mode.

The method may further include receiving the AC power through a mutualresonance between a resonator and a wireless power transmitter in thereceiving mode, and transmitting the AC power amplified by the poweramplifier through a mutual resonance between the resonator and awireless power receiver in the transmitting mode.

Examples of charge control apparatuses that operate in relay modes willbe described with reference to FIGS. 19A to 24.

FIGS. 19A and 19B illustrate examples of charge control apparatuses in awireless charging system.

Referring to FIG. 19A, an example of a charge control apparatus includesa resonator 1910, a switch 1920, an AC/DC converter 1930, a poweramplifier 1940, an integrated DC/DC converter 1950, and a controller1960.

The controller 1960 may determine a mode of the charge control apparatusto be one of a receiving mode, a relay mode, and a transmitting mode,based on a user input. In another example, the controller 1960 mayterminate the receiving mode when charging of a battery is completed,and control the charge control apparatus to operate in the relay mode orthe transmitting mode.

The controller 1960 may control a connection of the switch 1920 based onthe receiving mode, the relay mode, and the transmitting mode. In thereceiving mode, the resonator 1910 and the AC/DC converter 1930 may beconnected by the switch 1920. In the relay mode, the resonator 1910 maybe connected to an open port by the switch 1920 such that an impedanceof the resonator 1910 may increase. In the transmitting mode, theresonator 1910 may be connected to the power amplifier 1940. AlthoughFIG. 19A illustrates the switch 1920 as having three ports, varioustypes of switches having an open port may be used.

In the relay mode, when the impedance of the resonator 1910 increases, alarge portion of the power input into the resonator 1910 may bereflected by the resonator 1910. An amount of the power reflected by theresonator 1910 may be transferred to another terminal. In the relaymode, the charge control apparatus may reflect the input power using theresonator 1910 and transfer the power to the other terminal, rather thanreceiving the power.

The integrated DC/DC converter 1950 may step down a voltage level of aDC signal output from the AC/DC converter 1930 to a voltage levelrequired by a load, in the receiving mode, and step up a voltage leveloutput from the load to be greater than or equal to a support voltagelevel set in the power amplifier 1940, in the transmitting mode.

The descriptions provided with reference to FIGS. 3A and 3B may beapplied to the AC/DC converter 1930, the power amplifier 1940, and theintegrated DC/DC converter 1950.

Referring to FIG. 19B, the relay mode may be applied as an example ofthe transmitting mode. For example, a controller 1970 may control theintegrated DC/DC converter 1950 to provide a supply voltage Vdd of “0” Vwhile a mode is set to be the transmitting mode. Such a state maycorrespond to the relay mode. When a supply voltage of “0” V is appliedto the power amplifier 1940, the power amplifier 1940 may not operatesuch that the impedance of the resonator 1910 may increase. As theimpedance of the resonator 1910 increases, a large portion of the powerinput into the resonator 1910 may be reflected by the resonator 1910.The amount of power reflected by the resonator 1910 may be transferredto another terminal.

FIGS. 20 and 21 illustrate examples of charge control apparatuses in awireless charging system.

Referring to FIG. 20, a smart phone 2020 may operate in a relay mode.The smart phone 2020 may reflect a power input from a tablet 2010 andtransfer the power to a smart phone 2030. The configurations of chargecontrol apparatuses illustrated in FIGS. 19A and 19B may be included inthe smart phone 2020.

Referring to FIG. 21, a TV 2110 may be charged using a cable, andtransfer power wirelessly to other devices. A keyboard 2120 may operatein the relay mode. The keyboard 2120 may reflect a power input from theTV 2110, and transfer the power to a smart phone 2131, a laptop computer2132, a camera 2133, a tablet 2134, a smart phone 2135, and a camcorder2136. As the keyboard 2120 operates in the relay mode, a transmissionrange of the power provided by the TV 2110 may increase to be greaterthan or equal to a predetermined efficiency. In addition to the keyboard2120, various types of portable electronic devices may operate in therelay mode. The configurations of FIGS. 19A and 19B may be mounted onthe keyboard 2120. In another example, the configurations of FIGS. 19Aand 19B may be mounted on one of the smart phone 2131, the laptopcomputer 2132, the camera 2133, the tablet 2134, the smart phone 2135,and the camcorder 2136.

FIG. 22 is a block diagram illustrating an example of a charge controlapparatus in a wireless charging system operable in a receiving mode ora relay mode.

Referring to FIG. 22, the charge control apparatus includes a resonator2210, a switch 2220, an AC/DC converter 2230, a DC/DC converter 2240, aload 2250, and a controller 2260.

The controller 2260 may determine a mode of the charge control apparatusto be one of a receiving mode and a relay mode, based on a user input.In another example, the controller 2260 may terminate the receiving modewhen charging of a battery is completed, and control the charge controlapparatus to operate in the relay mode.

The controller 2260 may control a connection of the switch 2220 based onthe receiving mode, or based on the relay mode. In the receiving mode,the resonator 2210 and the AC/DC converter 2230 may be connected by theswitch 2220. In the relay mode, the resonator may be connected to anopen port, and an impedance of the resonator 2210 may increase.

In the relay mode, when the impedance of the resonator 2210 increases, alarge portion of a power input into the resonator 2210 may be reflectedby the resonator 2210. An amount of the power reflected by the resonator2210 may be transferred to another terminal. In the relay mode, thecharge control apparatus may reflect the input power using the resonator2210 and transfer the power to another terminal, rather than receivingthe power.

In the receiving mode, the DC/DC converter 2240 may step down a voltagelevel of a DC signal output from the AC/DC converter 2230 to a voltagelevel required by the load 2250.

In the receiving mode, the AC/DC converter 2230 may rectify a powerreceived at the resonator 2210, and convert the received power to a DCsignal.

FIGS. 23A and 23B are block diagrams illustrating examples ofapparatuses for charge control in a wireless charging system operable ina transmitting mode or a relay mode.

Referring to FIG. 23A, the charge control apparatus includes a resonator2310, a switch 2320, a power amplifier 2230, a DC/DC converter 2340, asystem 2350, and a controller 2360.

The controller 2360 may determine a mode of the charge control apparatusto be one of a transmitting mode and a relay mode, based on a userinput. For example, the system 2350 may supply power through an electricplug using a cable. In another example, the system 2350 may include abattery.

The controller 2360 may control a connection of the switch 2320 based onwhether the mode is the transmitting mode or the relay mode. In thetransmitting mode, the resonator 2310 may be connected to the poweramplifier 2340 by the switch 2320. In the relay mode, the resonator 2310may be connected to an open port by the switch, and an impedance of theresonator 2310 may increase.

In the relay mode, when the impedance of the resonator 2310 increases, alarge portion of a power input into the resonator 2310 may be reflectedby the resonator 2310. An amount of the power reflected by the resonator2310 may be transferred to another terminal. In the relay mode, thecharge control apparatus may reflect the input power using the resonator2310 and transfer the power to another terminal.

In the transmitting mode, the DC/DC converter 2340 may step up a voltagelevel output from the system to be greater than or equal to a supplyvoltage level set in the power amplifier 2330.

The power amplifier 2330 may convert the DC voltage stepped up by theDC/DC converter 2340 to an AC voltage based on a resonant frequency, andamplify the converted AC voltage. The power amplifier 2330 may adjust anamplification level based on an amount of power to be transmitted usingthe resonator 2310. The power amplifier 2330 may perform an operation ofa DC/AC converter converting a DC voltage to an AC voltage using aresonant frequency of the resonator 2310.

Referring to FIG. 23B, the relay mode may be implemented without use ofa switch. For example, in the transmitting mode, the controller 2370 maycontrol the DC/DC converter 2340 to provide a supply voltage Vdd of “0”V. Such a state may correspond to the relay mode. When a supply voltageof “0” V is applied to the power amplifier 2330, the power amplifier2330 may not operate and the impedance of the resonator 2310 mayincrease. As the impedance of the resonator 2310 increases, a largeportion of the power input into the resonator 2310 may be reflected bythe resonator 2310. An amount of the power reflected by the resonator2310 may be transferred to another terminal. By applying the scheme ofFIG. 23B, the relay mode may be implemented without use of a switch.

FIG. 24 is a diagram illustrating an example of a charge controlapparatus in a wireless charging system that operates in a transmittingmode or a relay mode.

Referring to FIG. 24, the charge control apparatus may be disposed in aninner portion or a lower portion of a table 2410. The charge controlapparatus of FIG. 24 may include the configurations illustrated in FIGS.23A and 23B.

The charge control apparatus may transmit a power provided through thepower amplifier 2430 using the resonator 2420, in the transmitting mode.The power transmitted using the resonator may be transferred to a smartphone 2440 and a smart phone 2450. The smart phone 2440 and the smartphone 2450 may be examples of portable terminals. Various types ofportable devices may be used as devices configured to transmit, relay orreceive power wirelessly.

When the charge control apparatus operates in the relay mode, the powertransmitted from the smart phone 2440 may be reflected by the resonator2420 and be transferred to the smart phone 2450.

The units described herein may be implemented using hardware components,software components, or a combination thereof. For example, a processingdevice may be implemented using one or more general-purpose or specialpurpose computers, such as, for example, a processor, a controller andan arithmetic logic unit, a digital signal processor, a microcomputer, afield programmable array, a programmable logic unit, a microprocessor orany other device capable of responding to and executing instructions ina defined manner. The processing device may run an operating system (OS)and one or more software applications that run on the OS. The processingdevice also may access, store, manipulate, process, and create data inresponse to execution of the software. For purpose of simplicity, thedescription of a processing device is used as singular; however, oneskilled in the art will appreciate that a processing device may includemultiple processing elements and multiple types of processing elements.For example, a processing device may include multiple processors or aprocessor and a controller. In addition, different processingconfigurations are possible, such as parallel processors.

The software may include a computer program, a piece of code, aninstruction, or some combination thereof, for independently orcollectively instructing or configuring the processing device to operateas desired. Software and data may be embodied permanently or temporarilyin any type of machine, component, physical or virtual equipment,computer storage medium or device, or in a propagated signal wavecapable of providing instructions or data to or being interpreted by theprocessing device. The software also may be distributed over networkcoupled computer systems so that the software is stored and executed ina distributed fashion. For example, the software and data may be storedby one or more non-transitory computer readable recording mediums.

As a non-exhaustive illustration only, a mobile terminal describedherein may be a mobile device, such as a cellular phone, a personaldigital assistant (PDA), a digital camera, a portable game console, anMP3 player, a portable/personal multimedia player (PMP), a handhelde-book, a portable laptop PC, a global positioning system (GPS)navigation device, a tablet, a sensor, or a stationary device, such as adesktop PC, a high-definition television (HDTV), a DVD player, aBlue-ray player, a set-top box, a home appliance, or any other deviceknown to one of ordinary skill in the art that is capable of wirelesscommunication and/or network communication.

The non-transitory computer readable recording medium may include anydata storage device that can store data which can be thereafter read bya computer system or processing device. Examples of the non-transitorycomputer readable recording medium include read-only memory (ROM),random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks,optical data storage devices. Also, functional programs, codes, and codesegments for accomplishing the example embodiments disclosed herein canbe easily construed by programmers skilled in the art to which theembodiments pertain based on and using the flow diagrams and blockdiagrams of the figures and their corresponding descriptions as providedherein.

While this disclosure includes specific examples, it will be apparent toone of ordinary skill in the art that various changes in form anddetails may be made in these examples without departing from the spiritand scope of the claims and their equivalents. The examples describedherein are to be considered in a descriptive sense only, and not forpurposes of limitation. Descriptions of features or aspects in eachexample are to be considered as being applicable to similar features oraspects in other examples. Suitable results may be achieved if thedescribed techniques are performed in a different order, and/or ifcomponents in a described system, architecture, device, or circuit arecombined in a different manner and/or replaced or supplemented by othercomponents or their equivalents. Therefore, the scope of the disclosureis defined not by the detailed description, but by the claims and theirequivalents, and all variations within the scope of the claims and theirequivalents are to be construed as being included in the disclosure.

What is claimed is:
 1. An electronic device for charge control, theelectronic device comprising: a resonator configured to receive a powerin a receiving mode, and relay an input power in a relay mode; a directcurrent-to-direct current (DC/DC) converter configured to step down avoltage level of a direct current (DC) signal output from an alternatingcurrent-to-direct current (AC/DC) converter to a voltage level requiredfor a load; and a controller configured to control the electronic devicefor charge control to operate in one of the receiving mode, atransmitting mode, and the relay mode, wherein the controller is furtherconfigured to connect the resonator to the AC/DC converter in thereceiving mode, and to connect the resonator to an open port in therelay mode.
 2. The electronic device of claim 1, wherein the controlleris further configured to control the electronic device for chargecontrol to operate in the relay mode when charging of the load iscompleted.
 3. The electronic device of claim 1, wherein the controlleris further configured to adjust an input impedance of the resonator tobe greater than or equal to a predetermined value in the relay mode. 4.The electronic device of claim 1, wherein the controller is furtherconfigured to open the resonator by controlling the DC/DC converter fora supply voltage of “0” volts to be supplied to a power amplifier in therelay mode.
 5. The electronic device of claim 1, wherein the controlleris further configured to disconnect the resonator to the AC/DC converterand connect the resonator to a power amplifier in the transmitting mode.6. The electronic device of claim 5, wherein the DC/DC converter isfurther configured to step up a voltage level output from the load to begreater than or equal to a supply voltage level for the power amplifierin the transmitting mode.
 7. The electronic device of claim 1, whereinthe DC/DC converter comprises: a first capacitor connected to a poweramplifier; a second capacitor connected to the load; and an outputvoltage determining unit configured to determine a voltage applied tothe first capacitor to be an output voltage of the DC/DC converter inthe transmitting mode, and to determine a voltage applied to the secondcapacitor to be an output voltage of the DC/DC converter in thereceiving mode.
 8. An electronic device for charge control, theelectronic device comprising: a resonator configured to transmit a powerin a transmitting mode, and relay an input power in a relay mode; adirect current-to-direct current (DC/DC) converter configured to step upa voltage level output from a load to be greater than or equal to asupply voltage level for a power amplifier in the transmitting mode; anda controller configured to control the electronic device for chargecontrol to operate in one of a receiving mode, the transmitting mode,and the relay mode, wherein the controller is further configured toconnect the resonator to the power amplifier in the transmitting mode,and to connect the resonator to an open port in the relay mode.
 9. Theelectronic device of claim 8, wherein the controller is furtherconfigured to control the electronic device for charge control tooperate in the relay mode when charging of the load is completed. 10.The electronic device of claim 8, wherein the controller is furtherconfigured to adjust an input impedance of the resonator to be greaterthan or equal to a predetermined value in the relay mode.
 11. Theelectronic device of claim 8, wherein the controller is furtherconfigured to open the resonator by controlling the DC/DC converter fora supply voltage of “0” volts to be supplied to the power amplifier inthe relay mode.
 12. The electronic device of claim 8, wherein thecontroller is further configured to disconnect the resonator to thepower amplifier and to connect the resonator to an alternatingcurrent-to-direct current (AC/DC) converter that converts a powerreceived wirelessly into a DC signal in the receiving mode.
 13. Theelectronic device of claim 12, wherein the DC/DC converter is furtherconfigured to step down a voltage level of the DC signal output from theAC/DC converter to a voltage level required for the load.
 14. Theelectronic device of claim 8, wherein the DC/DC converter comprises: afirst capacitor connected to the power amplifier; a second capacitorconnected to the load; and an output voltage determining unit configuredto determine a voltage applied to the first capacitor to be an outputvoltage of the DC/DC converter in the transmitting mode, and todetermine a voltage applied to the second capacitor to be an outputvoltage of the DC/DC converter in the receiving mode.
 15. A method forcharge control, the method comprising: controlling an electronic devicefor charge control to operate in one of a receiving mode, a transmittingmode, and a relay mode; adjusting an input impedance of the resonator inresponse to operating in the relay mode; and relaying an input powerbased on the adjustment.
 16. The method of claim 15, wherein thecontrolling comprises controlling the electronic device for chargecontrol to operate in the relay mode when charging of the load iscompleted.
 17. The method of claim 15, wherein the adjusting comprisesconnecting the resonator to an open port.
 18. The method of claim 15,wherein the adjusting comprises opening the resonator by controllingdirect current-to-direct current (DC/DC) converter for a supply voltageof “0” volts to be supplied to a power amplifier in the relay mode. 19.The method of claim 15, wherein the resonator is connected to analternating current-to-direct current (AC/DC) converter in the receivingmode, connected to a power amplifier in the transmitting mode, andconnected to an open port in the relay mode.